Planted Tank Enthusiast
Join Date: Mar 2013
Location: Baltimore, Maryland
$15 is nothing in the scheme of things. Initial fish loss isn't uncommon, and is just a minor setback. Any idea what the parasite is? And do you have any remaining life forms in the tank (fish, plants, shrimp, snails)?
I'd say write it off and start from scratch. Look into treatment options and start there. Remember to treat EVERYTHING in your tank. Decorations, glass, substrate, heaters, filters... anything that the parasite could live in/on. Best of luck!